Image quality selecting method and digital camera

ABSTRACT

Selection candidates for number of imaging pixels and for an image compression rate are displayed in a two-dimensional arrangement on a setting screen for setting an image quality, and combinations of selectable number of image pixels and a compression rate can be presented to a user. An instruction for moving a cursor which displays a selected position on the screen is received, and a setting can be changed to a number of pixels and a compression rate which are pointed by the cursor after a position of the cursor is designated. More specifically, numbers of pixels to be selected are 2400×1800, 1280×960, and 640×480, and compression rates to be selected are Fine, Normal, and Basic. When the user selects the number of pixels, candidates of the selectable compression rate for the number of pixels are displayed. A number of photographable images and remaining time for recording a moving image which are calculated from a capacity of a storage medium are preferably displayed in combination in accordance with combinations of the number of pixels and the compression rate.

This application is a Divisional of application Ser. No. 09/867,607filed on May 31, 2001, now U.S. Pat. No. 7,423,683 and for whichpriority is claimed under 35 U.S.C. §120; and this application claimspriority of Application No. 2000-162836 filed in Japan on May 31, 2000under 35 U.S.C. §119; the entire contents of all are hereby incorporatedby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image quality selecting methodapplied for a digital camera, and a camera which uses the image qualityselecting method.

2. Description of the Related Art

An image quality of a recorded image in a digital camera is usuallyspecified by two parameters, number of imaging pixels and an imagecompression rate. In a conventional digital camera, the number ofimaging pixels and the image compression rate are independent settingsections, and they are set individually, or a combination of a specificnumber of imaging pixels and a specific image compression rate isselected so as to set the number of imaging pixels and the imagecompression rate together.

However, the digital camera in which the number of pixels and thecompression rate are individually set has a disadvantage in that a typeof the compression rate cannot be confirmed at the time of selecting thenumber of pixels, while a type of the pixels cannot be confirmed at thetime of selecting the compression rate. Moreover, If the digital camerais a type in which the combination of the number of pixels and thecompression rate is selected, the combination is presented only by alist or, evaluation of an overall image quality is presented only bysimple symbols such as numbers of asterisks. As a result, contents ofthe combination of the number of pixels and the compression rate whichare actually set cannot be easily confirmed.

Further, if a menu for setting the number of imaging pixels and theimage compression rate is a special mode (such as a set-up mode) in theconventional digital camera, the number of photographable images cannotbe confirmed when the user selects the number of pixels and thecompression rate with the set-up mode. On the contrary, if a setting forthe number of pixels and the compression rate can be changed in a stillimage mode, number of photographable images is changed as changing thenumber of pixels and the compression rate; however, a camera with aninformation display screen in addition to a liquid crystal display (LCD)for image display does not display a remaining time for recording amoving image even though the number of photographable images is changed.

SUMMARY OF THE INVENTION

The present invention has been developed in view of the above-describedcircumstances, and has as its object the provision of an image qualityselecting method and a digital camera by which a pattern of combinationof the number of pixels and the compression rate can be presented for auser to understand easily; at the same time, the image quality selectingmethod and the digital camera achieves a function for aiding the user toselect a combination for an image quality.

In order to achieve the above-described objects, the present inventionis directed to an image quality selecting method comprising thefollowing steps: displaying selectable candidates for a number ofimaging pixels and image compression rates in a two-dimensionalarrangement on a setting screen for setting an image quality; presentingto a user combinations of selectable number of imaging pixels and theimage compression rates and at the same time receiving an instructionfor moving a cursor on the setting screen; and changing a setting to thenumber of pixels and the image compression rate which are pointed by thecursor after designating a position of the cursor.

According to the present invention, selectable candidates for the numberof imaging pixels and for the image compression rates are presented tothe user in the two-dimensional arrangement on the setting screen as auser interface for designating the two parameters, the number of imagingpixels and the compression rate, which specify the image quality, sothat the combination arrangement is designated by moving the cursor.Therefore, the user can understand at once the contents of thecombination of the number of imaging pixels and the image compressionrates, and can easily designate the image quality without beingconfused.

The user can select the image quality in consideration of the number ofphotographable images based on the number of imaging pixels and theimage compression rate which are selected with the cursor, specially bydisplaying the number of photographable images on the setting screen.

Instead of the number of photographable images, the remaining time forrecording a moving image is displayed on the screen while the movingimage is being recorded. In addition, a camera which can change thestill image mode and the moving image mode may also display the numberof photographable images and the remaining time for recording the movingimage together.

According to another embodiment of the present invention, information ona combination of the number of imaging pixels and the image compressionrate which have been set in a previous setting is stored; and when oneof the number of imaging pixels and the image compression rate ischanged by an operation of the user, the cursor automatically moves to aposition of the other of the number of imaging pixels and the imagecompression rate in the previous setting according to the storedinformation. Thus, contents which have been previously set can be easilyreset, improving operability of the digital camera.

When one of the number of imaging pixels and the image compression rateis changed by an operation of the user, the cursor can automaticallymove to a position of the other of the number of imaging pixels and theimage compression rate in a predetermined default.

In order to achieve the above-described method, the present invention isdirected to a digital camera, comprising: a taking lens; an imagingdevice that converts light which enters through the taking lens intoelectric signals; a signal processing part for processing the signalsoutputted from the imaging device; a recording instruction inputoperation part that instructs start of recording in order to obtain animage; a recording device that records an image in a storage medium, theimage being photographed in response to an operation of the recordinginstruction input operation part; a display device that displays asetting screen for setting an image quality; a display control devicethat displays selectable candidates for number of imaging pixels andimage compression rates on the setting screen of the display device, andpresenting combinations of selectable numbers of pixels and compressionrates; a cursor operating device that inputs an instruction for moving acursor, which points a selected position on the setting screen of thedisplay device; a designation instruction device that instructs adesignation of a selected position, which is indicated by the cursor;and an image quality setting device that changes a setting to the numberof pixels and the image compression rate which are pointed by the cursorin accordance with a designated instruction from the designationinstruction device.

The digital camera of the present invention further comprises acalculation device that calculating at least one of the number ofphotographable images and a remaining time for recording a moving imagefrom capacity of the storage medium with respect to each combination ofthe number of pixels and the image compression rate; and the at leastone of the number of photographable images and the remaining timecalculated by the calculation device with respect to each combination isdisplayed on the setting screen.

A table is prepared in which one of the selectable candidates for thenumber of imaging pixels and the image compression rate is horizontallylined up as a row, and the other is vertically lined up as a column onthe setting screen; and at least one of the number of photographableimages and the remaining time for recording a moving image for thecombination is displayed in each cell of the table.

The digital camera of the present invention further comprises a storagedevice that stores information on a combination of the number of imagingpixels and the image compression rate which have been set in a previoussetting; and when one of the number of imaging pixels and the imagecompression rate is changed, the display control device automaticallymoves the cursor to a position of the other of the number of imagingpixels and the image compression rate in the previous setting accordingto the information stored in the storage device.

When one of the number of imaging pixels and the image compression rateis changed, the display control device can move the cursor to a positionof the other of the number of imaging pixels and the image compressionrate in a predetermined default.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature of this invention, as well as other objects and advantagesthereof, will be explained in the following with reference to theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures and wherein:

FIG. 1 is a front view of a digital camera in an embodiment of thepresent invention;

FIG. 2 is a rear view of the digital camera in FIG. 1;

FIG. 3 is plan view of the digital camera in FIG. 1;

FIG. 4 is a bottom view of the digital camera in FIG. 1;

FIG. 5 is a right-side view of the digital camera in FIG. 1;

FIG. 6 is a block diagram showing an inner structure of the digitalcamera of the present embodiment;

FIGS. 7( a), 7(b), 7(c), 7(d) and 7(e) are views showing states wheresetting screens (menu screens) for an image quality are changed;

FIG. 8 is a view showing an example of presenting a selectablecombination of a number of pixels and a compression rates as well asnumber of photographable images;

FIG. 9 is a view showing another example of presenting a selectablecombination of the number of pixels and the compression rates as well asthe number of photographable images;

FIG. 10 is a view exemplifying a screen in a case where the combinationof the selectable number of pixels and the compression rates as well asthe number of photographable images are displayed together;

FIG. 11 is a view showing an example for changing display of the numberof photographable images after recording once from the state in FIG. 10;

FIGS. 12( a), 12(b) and 12(c) are views showing displays for anotherembodiment of the present invention;

FIG. 13 is a view showing a display example of a remaining time forrecording a moving image;

FIG. 14 is a view showing an example for changing display of the numberof photographable images and the remaining time for recording the movingimage after recording the moving image for 80 seconds from the state inFIG. 13;

FIG. 15 is a view showing an example for displaying the number ofphotographable images and the remaining time for recording the movingimage are displayed at the same time in a case where an image quality ofa still image and an image quality of a moving image can both bechanged;

FIGS. 16( a), 16(b) and 16(c) are views showing another display for thenumber of photographable images and the remaining time for recording themoving image; and

FIGS. 17( a), 17(b) and 17(c) are views showing still another display inaddition to the display of the number of photographable image and theremaining time for recording the moving image.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereunder preferred embodiments of the present invention will bedescribed in accordance with the accompanied drawings.

FIGS. 1-5 are a front view, a rear view, a plan view, a bottom view, anda right-side view, respectively, showing an external appearance of adigital camera 10. The digital camera 10 with an audio play isrectangular as shown in FIGS. 1-5 and pocket-sized.

A collapsible taking lens 12, a viewfinder window 14, an electronicflash 16, an electronic flash light adjusting sensor 18, a microphone19, and a self-timer lamp 20 are provided at a front face of the digitalcamera 10. A lens cover (not shown in FIG. 1 but shown in FIG. 6 with areference number 22) which is opened and closed at a collapsing positionof the taking lens 12 is also provided at the front face of the digitalcamera 10. In FIG. 1, the lens cover 22 is opened, and the referencenumber 23 corresponds with a grip of the camera.

A viewfinder 24, a mode dial 26, a right key 28, a left key 30, anup/down lever 32, a menu/execution key 34, a cancel/return key 36, adisplay key 38, a liquid crystal monitor 40, and so forth, are providedat a rear face of the digital camera 10 in FIG. 2. A mode dial 26changes functions of the camera in a camera mode, and a still image modefor recording a still image, a play mode for playing a photographedimage, or a moving image mode for recording a moving image is set byrotating the mode dial 26.

The right key 28, the left key 30, and the up/down lever 32 can inputinstructions of the four directions (right, left, up, and down). Theright key 28 and the left key 30 function as a forward button and areverse button, respectively, at the time of the play mode. The up/downlever 32 functions as a zoom lever for adjusting a magnification of anelectronic zoom at the time of a camera mode. The right key 28, the leftkey 30, and the up/down lever 32 function as operation buttons forselecting a menu from a menu list and for selecting the respectivesetting sections in the respective menu when a menu mode is set by themenu/execution key 34.

The menu/execution key 34 is used for shifting from a normal screen ofthe respective menu to a screen of one of the menu, or for instructing adesignation of the contents of the selection and execution(confirmation) of a process.

The cancel/return key 36 is used for canceling an item which has beenselected from the menu (cancellation) or for returning a previousoperating state.

The liquid crystal monitor 40 can be used as an electronic finder forconfirming an angle of view, and also can display an image and the likewhich are read out from a recorded image or a memory card (referencenumber 72 in FIG. 6) loaded in the camera. A display screen of theliquid crystal monitor 40 is used for selecting menu and for setting therespective setting items by using the right key 28, the left key 30, andthe up/down lever 32. Moreover, the liquid crystal monitor 40 displaysinformation such as the number of photographable images, an image numberof the reproduced image, presence of the electronic flash, a macro mode,image compression rates (quality), and a number of pixels.

A shutter release button 42, a mode setting switch 44 which is also usedas a power switch, and a strobe button 46 are provided on a top face ofthe digital camera 10. To record a moving image, the shutter releasebutton 42 is used also as a record button (a start/stop button forrecording a moving image).

The mode setting switch 44 in FIG. 3 is a slidable switch which islocked when moved to the right (moved at a audio mode position), but isnot locked when moved to the left. When the mode setting switch 44 ismoved to the right to be locked, an audio mode is set, and each time themode setting switch 44 is moved to the left, the camera mode and an OFFmode for turning off the power within the camera are alternately set.

In a case where the audio mode is set by the mode setting switch 44, therespective types of switches of the camera do not function, and only aswitch of a remote control (not shown) is accepted which has an earphone(headphone) connected with a remote control terminal described later(reference number 56 in FIG. 5). In a case where the remote control isnot connected with the remote control terminal 56 despite that the audiomode is set by the mode setting switch 44, the power of the camera isstill turned off, and the power of the camera is turned ON by operatingthe remote control after connecting the remote control with the remotecontrol terminal 56.

A battery cover 48 which also serves as a slot cover for the memory card(a smart media in the present example) and a screw hole 50 for a tripodare provided to the bottom face of the digital camera in FIG. 4. Aspeaker 52, an audio/video output (VIDEO OUT) terminal 54, the remotecontrol terminal 56 including an audio output terminal, a digital (USB)terminal 58, and a power input terminal 50 are provided at a side faceof the digital camera 10 in FIG. 5.

FIG. 6 is a block diagram showing an inner structure of the digitalcamera 10. In FIG. 6, a central processing unit (hereafter called a CPU)70 controls the respective circuits within the digital camera 10 inaccordance with inputs from the mode setting switch 44, the mode dial26, the shutter release button 42, an operation part 61, and the remotecontrol which is not shown. The operation part 61 is a block whichincludes input operation means such as the above-mentioned right key 28,left key 30, up/down lever 32, menu/execute key 34, cancel/return key36, and display key 38. A reference number 71 is assigned to an innerbus.

When the mode setting switch is set from the OFF mode to the cameramode, the CPU 70 detects the setting, and turns on the power within thecamera while controlling to open the lens cover 22. When the modesetting switch 44 is set from the camera mode to the OFF mode or to theaudio mode, the CPU 70 detects the setting, and controls to completelyclose the lens cover 22.

In order to open the lens cover at that time, the CPU 70 outputs asignal for rotating a motor 64 forward via a driver 62, whereas the CPU70 outputs a signal for rotating the motor 64 in reverse in order tocompletely close the lens cover 22. The CPU 70 also controls the takinglens 12 to move at a collapsing position before completely closing thelens cover 22.

When the shutter release button 42 is pressed after the camera mode isset by the mode setting switch 44 and the still image mode is set by themode dial 62, the CPU 70 detects the setting and instructs the digitalcamera 10 to perform a still recording, then records image data of oneimage obtained by the recording in the memory card 72. In other words,the CPU 70 controls focusing as well as exposure, and forms a subjectlight on a light receiving surface of a solid state imaging device(hereafter called CCD) 74 through the taking lens 12.

The CCD 74 converts the subject light formed on the light receivingsurface into a signal charge in an amount corresponding with an amountof the subject light, and the signal charge accumulated in this manneris sequentially read out as a voltage signal corresponding with thesignal charge. The voltage signal sequentially read out from the CCD 74is added to a coefficient double sampling circuit (CDS circuit) 76, andR, G, and B signals for the respective pixels are processed through asampling holding and are amplified, then are added to an A/D converter78. The A/D converter 78 converts the R, G, and B signals which aresequentially added from the CDS circuit 76 into digital R, Q and Bsignals of 10 bits (0-1023) and outputs the digital R, G, and B signalsto an image signal processing circuit 80.

The image signal processing circuit 80 performs the predetermined imageprocesses such as a synchronization for converting the dot-sequential R,G, and B signals added from the A/D converter 78 into synchronizedsignals, a white balance adjustment, a gamma correction, and a YC signalprocessing. A brightness signal Y and a chroma signal Cr and Cb (YCsignal) which are produced by the YC signal processing of the imagesignal processing circuit 80 are recorded in the memory card 72 via amedium control circuit 84 after being compressed into a predeterminedformat (e.g. JPEG format) by a compressing/decompressing circuit 82.

The storage medium is not limited to the smart media; a PC card, acompact flash, a magnetic disk, an optical disk, an optical magneticdisk, a memory stick, and the like; a variety of readable and writablemedia may be used in accordance with electronic, magnetic, opticalformats, or combinations of the formats. A signal processing device andan interface corresponding with a medium being used are applied. Astructure is also acceptable in which plural storage media areattachable to a body of the camera regardless of types of the storagemedia. In addition, a device for storing the image data and the musicdata is not limited to a removable medium which can be attached anddetached to and from the body of the camera but may be a storage medium(inner memory) which is built in the camera.

When the camera mode is set by the mode setting switch 44 and the movingimage mode is set by the mode dial 26, recording of the moving image ispossible, and a recording operation starts by pressing down the shutterrelease button 42. If the shutter release button 42 is pressed again,the recording stops. Another recording operation may be possible inwhich the recording is performed while pressing the shutter releasebutton 42 continuously, and the recording stops by releasing thepressing. Moving image data is recorded in the memory card 72 in amotion JPEG format, for example.

On the other hand, when the camera mode is set by the mode settingswitch 44 and the play is set by the mode dial 26, an image file of thelast image which is recorded in the memory card 72 is read out via themedium control circuit 84. Compressed data of the read out image file isdecompressed into YC signals via the compressing/decompressing circuit82.

The YC signals are converted into color composition video signals in theNTSC format via an image play circuit 86 and a video encoding circuit88, and is outputted to the liquid monitor 40 as well as the audio/videooutput terminal 54 (refer to FIG. 5). By the process, an image of thelast image which is recorded in the memory card 72 is displayed on theliquid crystal monitor 40, whereas an image of the last image isdisplayed on a TV (not shown) if the TV is connected with theaudio/video image output terminal 54.

After that, when the right key 28 is pressed, images are sequentiallyfed, and when the left key 30 is pressed, the images are fed in reverse.The image file at a position of a fed image is read out from the memorycard 72, and the image is played on the liquid crystal monitor 40 in thesame manner as described above. When the images are sequentially fedwhile the image of the last image is displayed, the image file of thefirst image which is recorded in the memory card 72 is read out, and theimage of the first image is played in an image display device such asthe liquid crystal monitor or the TV.

If the file to be reproduced is a moving image file, the top image ofthe moving image is displayed as a representative image, and the screenchanges to a screen to receive an instruction for starting play of themoving image.

Next, an audio play function of the digital camera 10 will be described.The audio play function plays a music file recorded in a format such asthe MP3 (MPEG-1 Audio Layer-III) in the memory card 72. When the audiomode is set by the mode setting switch 44 and the remote control with anearphone is connected with the remote control terminal 56 in that state,the power within the camera is turned on, so the audio play is possible.In the audio mode, the CPU 70 receives a remote control signal only fromthe remote control, and thus does not accept any switch inputs exceptinputs from the mode setting switch which is also used as a power switchfor the camera.

When a play button of the remote control is pressed while the digitalcamera 10 is set at the audio mode, the music file is read out from thememory card 72 via the medium control circuit 84. Assume that the musicfile is directly downloaded into the memory card 72 from a personalcomputer, or via the digital (USB) terminal 58 (refer to FIG. 5) of thedigital camera 10.

The compressed data of the image file which is read out from the memorycard 72 is decompressed to music data via the compressing/decompressingcircuit 82. The music data goes through processes such as D/A conversionby an audio processing circuit 90, and is converted into an analog audiosignal. The converted audio signal is amplified by an audio play circuit92, and is outputted as audio via an audio output terminal and anearphone (not shown) within the remote control terminal 56.

A procedure will be described from now on for setting an image qualityof the digital camera 10 which is constructed as described above. Whenthe user turns on the mode setting switch 44 which is also used as apower switch, the digital camera is activated in the camera mode. Thedigital camera 10 is in a state in which recording is possible aftersetting the still image mode or the moving image mode by the mode dial26. When the user presses the display key 38 at that time, the liquidcrystal 40 displays a real time image which is captured by the CCD 74.When the mode dial 26 is set, the image data is read out from the memorycard 72, and the liquid crystal display 40 displays one image which ismost recently recorded.

When the user presses the menu/execute key in the respective still imagemode, moving image mode, and play mode, a menu screen corresponding withthe modes is displayed. For example, when the user presses themenu/execute key 34 in the still image mode (or under the moving imagemode), menu items related to the still image mode (or the moving imagemode) are displayed; assume that an item for “image quality setting” isincluded in the menu items. When the item “image quality setting” isselected by the right key 28, the left key 30, or the up/down lever 32,a menu screen for image quality setting is displayed as shown in FIG. 7(a).

In the present example, the number of imaging pixels can be selectedfrom 2400×1800, 1280×960 and 640×480; the image compression rates can beselected from the three types: Fine mode, Normal mode, and Basic mode.Order of listing the image quality in those modes is from superior topoor: the Fine mode for the best, the Normal mode for the second best,and the Basic mode for the third. For example, the Fine mode correspondswith ¼ (JPEG) compression, the Normal mode corresponds with ⅛ (JPEG)compression, and the Basic mode corresponds with 1/16 (JPEG)compression.

Suppose that the “compression rate” is a rate of amount of data afterbeing compressed with respect to an amount of the original data, thelarger the compression rate, the less (lower) the level of compressionis, thus the better the image quality is. On the other hand, if thedenominator of a fraction where the amount of the original data iscompared with the amount of the data after the compression is defined asa “compression rate”, the larger the denominator is, the lower the imagequality is.

Some of the cameras may have so-called an uncompression mode which doesnot perform the compression. The uncompression is a case where thecompression of the best image quality is selected; thus, selecting theuncompression mode is also considered as “selecting the compressionrate”.

In the menu screen in FIG. 7, the number of imaging pixels is indicatedas “pixel” and the image compression rate is indicated as “quality”, and2400×1800, 1280×960, and 640×480 are indicates as “2400”, “1280”, and“640”, respectively. In the menu screen, a cursor points at a positionof a combination of the number of pixels and the compression raterelated to the current setting. A color of the position of the cursor inFIG. 7 changes to a different color so as to be distinguished fromcolors of other items displayed on the screen.

In FIG. 7( a), the cursor is at a position of “pixel=2400” and“quality=Normal”. When the user presses the right key 28 or the left key30 in that state, the compression rate can be changed while unchangingthe number of pixels “2400”. For example, when the user presses theright key 28, the cursor is at a position of “Basic” as shown in FIG. 7(b), and when the user presses the left key 30 in the state of FIG. 7(b), the display returns to the display in FIG. 7( a).

On the current cursor position (e.g. “Normal” in FIG. 7( a) and “Basic”in FIG. 7( b)), a “triangle pointed to the right” 94R and a “trianglepointed to the left” 94L indicate to the user that the compression ratescan be changed by operating the right key 28 or the left key 30.However, a corresponding triangle is not displayed when the operationwith keys is not valid.

The number of pixels is changed by moving the up/down lever 32. Movingup the up/down lever 32 means pressing down an up key whereas movingdown the up/down lever 32 means pressing down a down key. When thenumber of pixels is changed by the up/down lever 32, selectablecandidates for the compression rates in the selected number of pixelsare displayed and at the same time the position of the cursor moves.When the user moves down the up/down lever 32 in the screen of FIG. 7(a) so as to change the number of pixels to “1280”, the candidates forthe compression rate related to “2400” disappears from the screen, andinstead the selectable candidates for the compression rate related to“1280” appears on the screen. If the number of pixels is “1280” in thisexample, one of “Fine” or “Normal” can be selected but not “Basic”, so“Basic” is not displayed.

The cursor is at a position of the compression rate which has been mostrecently set in “1280” (in this case “Fine”). If there is no history ofsetting, the cursor is positioned at a suitable default position (or ifpossible, a position which is currently set). As to changing the numberof pixels, a “pointed-down triangle” 96D or a “pointed-up triangle” 96Uor both are displayed at the right of the current position of thecursor, and they indicate to the user that the number of pixels can bechanged by moving the up/down lever 32. If the key is not valid, thecorresponding triangle is not displayed.

The compression rate can be changed to “Normal” as shown in FIG. 7( d)by operating the right key 28 (in this case only the right key 28 isvalid) in FIG. 7( c). The display returns to the display in FIG. 7( c)by pressing the left key 30 in FIG. 7( d).

When the user moves down the up/down lever 32 in a state of FIGS. 7( c)and 7(d), the cursor moves at a position of the number of pixels “640”in FIG. 7( e), and the selectable candidates for the compression raterelated to “1280” disappears from the screen, then instead theselectable candidates for the compression rate for “640” appears on thescreen. In the present example, only “Normal” can be designated in thenumber of pixels “640”, and “Fine” and “Basic” cannot be selected; thusonly “Normal” is displayed, and other candidates are not displayed.

The digital camera 10 limits the selectable compression rates dependingon the number of pixels; however, all the compression rates may beselected for the respective number of pixels. In other words, the threetypes of compression rates may be selected with respect to the threetypes of number of pixels, so there are nine combinations to be selectedin total. The number of selectable candidates can be so designed as tobe suitable depending on a case; a two-dimensional display is possibleas long as one of the number of pixels and the compression rate has morethan two types of selectable candidates. Distinguishing the candidatesby colors is also preferable.

At the bottom row in the image quality setting screen (the menu screenof the pixel/quality setting) in FIGS. 7( a)-7(d), an operation guidance“set→[execute]” and “stop→[cancel]” are displayed in order to present amethod for designating an item in the menu screen. “Execute key”, thatis, the menu/execute key 34 in FIG. 2 is used for designating thesetting at the current cursor position as a set item, and contents ofsetting are set by pressing down the menu/execute key 34. “Cancel key”,that is, the cancel/return key 36 in FIG. 2 is used for returning to apreviously set item or for exiting from the menu screen.

If exiting from the menu of the pixel/quality setting, the compressionrate which is previously set with respect to the number of pixels exceptthe number of pixels of an item which is designated the last is storedin a nonvolatile memory (e.g. an inner memory of the CPU 70).

If entering into the menu of the next pixel/quality setting and moved onto the number of pixels by operation of the user, the cursor is moved byfollowing the stored data of the nonvolatile memory. Thereby, theprevious setting state can be easily reset. The default value of thecompression rate which is the selectable candidate for each number ofpixels may be specified beforehand, and the cursor is moved at aposition indicated by the default value.

As an alternative one of the above-described embodiment, the number ofphotographable images is preferably displayed under the setting duringwhich the number of images and the compression rate are selected. TheCPU 70 calculates the number of photographable images from capacity ofthe memory card 72 with respect to combinations of the number of imagingpixels and the image compression rates. The number of photographableimages which are thus calculated are displayed in a predeterminedposition in the setting screen, for example, at the upper right portionof the screen as shown in FIG. 8. FIG. 8 displays a case where imagescorresponding with 77 still images can be recorded under the set numberof pixels “2400” and the set compression rate “Normal”.

The position to display the number of photographable images is notlimited to the position shown in FIG. 8; the number of photographableimages may be displayed at the right bottom portion of the screen, orany blank space other than the area for displaying selectable candidatesfor the number of pixels and the image compression rates. Moreover, asseen from FIG. 9, the number of photographable images may also bedisplayed above (or below) the current position of the cursor. In themanner described above, the number of photographable images undercombinations related to the selections is displayed before finallydeciding the setting for the image quality; thereby the user candesignate the image quality in consideration of the number ofphotographable images.

FIG. 10 shows another embodiment of the present invention in which thethree types of number of imaging pixels of 2400×1800, 1280×960 and640×480 can be selected, and the three types of image compression rates,“Fine”, “Normal”, and “Basic” can be selected. In the present example inFIG. 10, a cross table on which the selectable candidates “2400”,“1280”, and “640” for the number of image pixels are lined vertically(column) and the selectable candidates “Fine”, “Normal”, and “Basic” forthe image compressions are lined horizontally (row). In each cell(square) of the table, the number of photographable images in a case ofselecting a combination of the number of pixels and the imagecompression rate corresponding with the cell is displayed. However, dueto the use of the camera, a cell corresponding with an unselectable pairof the number of pixels and the image compression rate is not displayedand the cursor does not move.

FIG. 10 shows the maximum number of photographable images in a smartmedia of 64 MB. For example, with a combination of the number of pixels“2400” and the compression rate of “Normal” corresponding with thecurrent position of the cursor, the number of photographable images is77 by referring to the capacity of the memory card. Instead of thecursor, a image may be displayed on the corresponding cell.

The user selects the compression rates with the right key 28 or the leftkey 30, and designates the image quality by selecting the number ofimage pixels with the up/down lever 32. When selecting, the user canrefer to the number of photographable images displayed on the cell.

Each time the image data is stored into the memory card 72, the numberof photographable images is preferably calculated again with respect tothe residual capacity of the memory card 72 so as to update display.FIG. 11 shows the number of photographable images after one taking underthe setting “2400” for the number of pixels and the setting “Normal” forthe image compression rate in the state of FIG. 10. If the number of thecalculated photographable images is “0 images”, the cursor is set to beunmovable with respect to the corresponding cell, or the cell is notdisplayed in order to avoid selecting. Moreover, a user interface isalso possible in which an alarm sounds when the cursor moves at aposition indicating the number of photographable images “0 images” sothat the user can be informed of changing the setting.

In the embodiment presented in FIG. 7, the selectable candidates for thenumber of pixels are determined as a reference, and the selectablecandidates for the image compression rates with respect to the number ofpixels involved in the selection are displayed. In reverse to theembodiment related to FIG. 7, however, an embodiment is allowable inwhich the selectable candidates for the compression rates are determinedas a reference, and the selectable candidates for the number of pixelswith respect to the compression rate involved in the selection arepresented. For example, as seen from FIG. 12, the selectable candidatesfor the image compression rates, “Fine”, “Normal”, and “Basic” arevertically arranged and are displayed on the screen. When thecompression rate “Fine” is selected, the selectable candidates for thenumber of image pixels “2400” and “1280” are horizontally lined anddisplayed as shown in FIG. 12( a).

When the compression rate “Normal” is selected, the selectablecandidates for the number of image pixels “2400”, “1280”, and “640” aredisplayed as seen from FIG. 12( b), and when the compression rate“Basic” is selected, “1280” is displayed at a column for the number ofpixels as shown in FIG. 12( c). As indicated in the series of FIG. 12,the selectable number of pixels can be limited depending on thecompression rates, so the number of image pixels of all types may beselected with respect to each compression rate.

In the embodiment described above, the digital camera with an audio playfunction is described first; however, the embodiments of the presentinvention is not limited to such embodiment. The present invention canalso be applied to a digital still camera which is exclusively used forrecording still images, a digital moving image camera which isexclusively used for recording moving images, and a video camera whichcan record both still images and moving images.

Now, an alternative one of the embodiments described above will beillustrated.

When the user selects a desired number of pixels and compression rate onthe menu screen for the image quality selection, a state of the storagemedium (e.g. recordable capacity) is checked, and the number ofphotographable still images and the remaining time for taking a movingimage under the image quality involved in the selecting are preferablycalculated so as to display information related to the number ofphotographable images and the remaining time for taking a moving image.

FIG. 13 shows an example of the display screen to which a display of theremaining time for taking a moving image is added. The image quality forthe photographed still image can be selected in the menu screen of theimage quality selection, and the image quality of the moving image issupposed to be fixed. The number of photographable images is displayedin each cell (selectable cell) of the table in which the selectablecandidates for the number of pixels and the image compression rates arepresented in a two-dimensional manner, and the remaining time for takinga moving image is displayed (40 seconds in the present case) at theupper right portion out of the column in the table. A cell with anunselectable combination is not displayed, and the cursor is prohibitedfrom moving to the position of the cell, or the user is informed by analarm that the cell cannot be selected. FIG. 13 indicates the maximumnumber of photographable images in an unrecorded recording card of thesmart media of 64 MB.

FIG. 14 shows contents of the screen which displays the number ofphotographable images and the remaining time for taking a moving imageafter recording a moving image for 80 seconds in the moving image modein the state of FIG. 13. The remaining time for taking a moving image isthen “330 seconds”, and the number of photographable images iscalculated again corresponding with a used amount of the storage mediumaccompanied by recording the moving image. Display is constantly updatedby checking the residual amount of the storage medium.

FIG. 15 shows an example in which recording a still image, recording amoving image, and changing the image quality are all possible. In FIG.15, the number of pixels “1280” and “640” are selectable with regard totaking a moving image. In this case, the three types of compressionrates, “Fine”, “Normal”, and “Basic” can be selected when the number ofpixels is “1280” while the compression rate to be selected is only“Fine” when the compression rate is “640”. Patterns of selectablecombinations are not limited to the one mentioned above, and may bedesigned to suit the use of the camera.

The number of photographable images as well as the remaining time forrecording a moving image are displayed in each cell of the table whichdisplays the selectable candidates for the number of pixels andcompression rates in the two-dimensional manner. In FIG. 15, the numberof photographable images is displayed at an upper level of each cellwhile the remaining time for recording a moving image is displayed at alower level of the cell. For example, with the number of pixels “2400”and the compression rate “Normal”, the number of photographableimages=77 images and the remaining time for recording a moving image=12seconds.

FIG. 16 shows still another example for displaying the remaining timefor recording a moving image. As described with regard to the embodimentin FIG. 7, in a case with a menu format which represents the selectablecandidates for the compression rates under the number of pixels involvedin the selecting, the number of pixels is selected first in the imagequality selection and the number of photographable images and theremaining time for recording a moving image which are pointed by thecursor are simultaneously displayed at the upper right portion out ofthe column where the selectable candidates are displayed in the samemanner as in FIG. 13. The cursor in FIG. 16( a) points a position of thecombination of the number of pixels “2400” and the compression rate“Normal”, the cursor in FIG. 17( b) points a position of the combinationof the number of pixels “1280” and the compression rate “Normal”, andthe cursor in FIG. 17( c) points a position of the combination of thenumber of pixels “640” and the compression rate “Normal”.

FIG. 16 indicates an example in which the image quality selection of thestill image to be photographed is possible whereas the image qualityselection of a moving image to be taken is not possible (the imagequality for the moving image is fixed); however, if the image quality ofthe moving image can be changed, the display for the remaining time forrecording a moving image is also changed in accordance with thecombinations involved in the selecting. In that case, if the calculatedremaining time for recording a moving image is “0 seconds”, the time isnot displayed, or the user is informed by an alarm that recording of themoving image is not possible.

FIG. 16 indicates the menu format in which the compression rate isselected corresponding with selecting of the number of pixels bydetermining the selectable candidates for the number of pixels as thereference. Likewise, as seen from FIG. 17, a menu format is alsoapplicable which presents the selectable candidates for the number ofpixels corresponding with selecting of the compression rates bydetermining the selectable candidates for the compression rates as thereference.

Moreover, another embodiment is also possible in which the remainingtime for recording a music file (hereunder called a remaining time forregistering the music file) is calculated from the capacity of thestorage medium, and information of the remaining time for registeringthe music file is displayed as well as the number of photographableimages and the remaining time for recording a moving image. Further, ifsetting of the sound quality can be changed when the music file isrecorded, the present invention can be applied to the screen forchanging the setting.

For example, in a case where the quality of sound at the time ofrecording the music file is specified by the two parameters, the numberof sampling (number of sound data) and the compression rate, theselectable candidates for the number of sampling and the compressionrates are displayed in the two-dimensional manner, and the user candesignate a desired combination from the display screen. The remainingtime for registering the music file with respect to the combinations ofthe number of sampling and the compression rates to be selected isdisplayed on the display screen. By this embodiment, the user can easilyset the sound quality by referring to the remaining time for registeringthe music file.

As described above, according to the image quality selecting method andthe digital camera of the present invention, the selectable candidatesfor the number of imaging pixels and the image compression rates whichare prepared beforehand are displayed in a two-dimensional arrangement;thus the user can understand at once the contents of the combinations ofthe number of imaging pixels and the image compression rates, and caneasily designate the image quality.

Furthermore, according to the present invention, the number ofphotographable images and the remaining time for recording a movingimage are calculated with respect to each selectable combination of thenumber of imaging pixels and the image compression rates, and the numberof photographable images and the remaining time for recording a movingimage are displayed on the selecting screen. Therefore, the user candesignate the image quality by referring to the display (the displayednumber of photographable images and the remaining time for recording amoving image).

In a conventional camera, the number of photographable images and theremaining time for recording a moving image could not be determinedunless setting of the number of pixels and the compression rates isselected. However, according to the present invention, the number ofphotographable images and the remaining time for recording a movingimage are displayed when the number of pixels and the image compressionrates are selected, whereby the user is aided when determining the imagequality.

It should be understood, however, that there is no intention to limitthe invention to the specific forms disclosed, but on the contrary, theinvention is to cover all modifications, alternate constructions andequivalents falling within the spirit and scope of the invention asexpressed in the appended claims.

1. An image quality selecting method, comprising: displaying acombination of selectable candidates by associating both candidates fora number of imaging pixels and image compression rates intwo-dimensional arrangement on a setting screen for setting an imagequality; collectively setting and presenting to a user a combination ofselectable candidates of a number of imaging pixels and an imagecompression rate by selecting one candidate from amongst the displayedcombination of selectable candidates and simultaneously receiving aninstruction for moving a cursor on the setting screen; and changing asetting to the number of pixels and the image compression rate which arepointed by the cursor after designating a position of the cursor.
 2. Adigital camera, comprising: a taking lens; an imaging device thatconverts light which enters through said taking lens into electricsignals; a signal processing part for processing the signals outputtedfrom said imaging device; a recording instruction input operation partthat instructs start of recording in order to obtain an image; arecording device that records an image in a storage medium, the imagebeing photographed in response to an operation of said recordinginstruction input operation part; a display device that displays asetting screen for setting an image quality; a display control devicethat displays a combination of selectable candidates by associating bothcandidates for a number of imaging pixels and image compression rates ina two-dimensional arrangement on the setting screen; a image qualitysetting device that collectively sets and presents to a user acombination of selectable candidates of a number of imaging pixels andan image compression rate by selecting one candidate from amongst thedisplayed combination of selectable candidates; a cursor operatingdevice that simultaneously receives an instruction for moving a cursoron the setting screen; a designation instruction device that instructs adesignation of a selected position, which is indicated by said cursor;and wherein said image quality setting device changes a setting to thenumber of pixels and the image compression rate which are pointed by thecursor in accordance with a designated instruction from said designationinstruction device.
 3. An image acquisition apparatus, comprising: amemory for storing an image; and to at least one processor operablycoupled to the memory, wherein at least one processor executesinstructions for displaying a combination of selectable options byassociating both options for a number of imaging pixels quantities andimage compression rates in a two-dimensional arrangement, collectivelysetting a combination of selectable options of a number of imagingpixels quantities and an image compression rate by selecting one optionfrom amongst the displayed combination of selectable options, andsimultaneously receiving an instruction for selecting independently atleast one of an image compression rate and an image pixel quantity fromthe displayed options using a cursor for use in processing the image.